George Osborne still has a fortnight before he delivers his budget; but even at this distance, and despite all the usual Treasury secrecy, it is possible to place three bets on what will happen on 23 March. First, the chancellor will do something about petrol prices. That much is clear from statements this week such as "I am looking, of course, at fuel duty … I understand how families are hit hard by the rising cost of oil around the world … and I am seeing what I can do to help". Such unusually heavy hints are difficult to back away from, and it appears more than likely that Mr Osborne will scrap the penny rise in fuel duty planned for April. The chancellor will most probably claim that he is simply undoing a tax rise designed by his Labour predecessor, without fully explaining why he initially accepted it.

Second, one can predict that any such move by Mr Osborne will be pounced upon by his shadow, Ed Balls, as being mere copy-cattery. Of course, Mr Balls will say, I was calling for this last month. What took the chancellor so long?

The final prediction one can make is that however Mr Osborne may present his U-turn or Mr Balls is congratulated for the snookering of his opponent, that will not make this reversal of policy any more justified.

The reason why politicians are coming under such pressure to act on fuel prices is obvious: by the AA's estimates, unleaded petrol will break the £6-a-gallon mark this week, while a litre of diesel is already going for an average of £1.37 (the equivalent of £6.22 a gallon). Brent crude has shot up by over $10 a barrel in the past month alone and, for as long as the unrest continues in the Middle East, it is anyone's guess how high fuel prices may go. That means motorists and businesses are likely to see big dents in their budgets and profits. And as Tony Blair learned during the fuel protests that marked the start of last decade, politicians mess with motorists at their peril.

None of this makes a cut in fuel duty the right decision. This surge has been driven by market jitters over instability in Saudi Arabia. If traders are satisfied that Opec's biggest producer will not face serious unrest, crude prices will drop back down again. And the party that battled elections under the slogan Vote Blue, Go Green should be responding to higher fuel prices by supporting low-income groups and investing in public transport – not by giving a taxpayers' subsidy to every motorist, whether they are a millionaire or a milkman. To do so even while cutting spending on welfare and public services shows a sense of priorities informed by politics rather than fairness or considerations of environmental sustainability. That cannot be right, whichever party comes up with the idea.